Samir Kassir, a 45-year-old newspaper columnist, was killed on Thursday by a bomb that exploded under his car in the Christian Beirut neighbourhood of Ashrafieh.
On Saturday, he was laid to rest in Saint Mitr Cemetery, a few hundred meters from where he died.
Lebanon's opposition, which blamed Syria and its local allies for the killing, asked government officials not to attend the funeral.
More than 2000 people watched as Kassir's coffin was carried from the offices of his newspaper, An-Nahar, in Beirut's downtown Martyrs' Square, by pallbearers including the newspaper's director-general, Gibran Tueini.
Mourners threw rose petals on the coffin as it made its way to nearby Saint George's Greek Orthodox church for Kassir's funeral.
The funeral was attended by several opposition leaders, including Walid Jumblatt, Amine Gemayel and Saad Hariri, son and heir of former prime minister Rafik Hariri, who was killed by a huge car bomb in Beirut on 14 February.
Kassir's wife, Giselle Khoury, and daughters Layan and Maysa wept silently in front of his coffin during the funeral Mass.
Khoury, a journalist with Al-Arabiya television, had demanded an international investigation into the death of husband, who held French and Lebanese citizenship.
Kassir was critical of Syria's
influence over Lebanon
"His pen will be the pen that we will continue to write with," said Nayla Tueini, an An-Nahar journalist and daughter of the daily's director-general. "Our mission is to follow Samir's path."
After the funeral prayers, young members of Kassir's Democratic Left Movement carried the coffin outside the church chanting, "Samir, we are your dream".
Hundreds of people marched behind the coffin as it was carried to the cemetery.
Lahoud resignation call
Lebanon's anti-Syrian opposition, which has demanded for months that pro-Syrian President Emile Lahoud resign, called for demonstrators to gather near the presidential palace on Monday.
Opposition leader Elias Atallah said the protesters would lay a wreath "that clearly points to the direct responsibility of this security regime".
Lahoud has condemned the killing of Kassir, but the opposition was unimpressed.
"His pen will be the pen that we will continue to write with"
One of the placards carried during the funeral read: "Samir's martyrdom is one of Emile Lahoud's miracles."
Syria pulled all its troops out of Lebanon in April after three decades, and Lebanon is in the midst of a four-round parliamentary election that the anti-Syrian opposition hopes will end Damascus' control of the legislature.
Voting takes place on Sunday in southern Lebanon as part of the elections, which run until 19 June.
European parliamentarians Jose Ignacio Salafranca and Carlos Carnero, both members of a European mission to monitor Lebanon's elections, condemned Kassir's killing.
Freedom of speech
In a statement, they said the assassination was an attack against the freedom of speech of the Lebanese people, especially against the background of the parliamentary elections being held.
On Friday, about 200 journalists and politicians, many holding black pens to symbolise freedom of expression, stood for an hour in Martyrs' Square in silent tribute to Kassir, as bells tolled in nearby churches.
Opposition spokesmen blamed Syria for the assassination - a charge Syria denied - and accused Damascus of continuing to interfere in Lebanon's politics.
Emile Lahoud was asked not to
attend the funeral
Justice Minister Khaled Kabbani on Saturday appointed judge Sami Sidki to investigate Kassir's killing, but there is widespread scepticism in Lebanon about the state's ability to investigate political crimes.
FBI agents are assisting Lebanon's investigation into Kassir's assassination, Lebanese Justice Ministry officials said on Friday.
France's Interior Ministry said five French investigators were scheduled to arrive in Lebanon to assist with the inquiry.